Area Central Police Cmdr. Brendan Deenihan said it's "reasonable" to believe Harris killed the four in retaliation for his father's fatal shooting.

"I don't know what Harris was thinking, because Harris didn't tell us what he was thinking," Deenihan told reporters at a news conference. "A reasonable belief would be that his father got killed, and then subsequently he shoots and kills these four people."

Deenihan said Harris has not confessed to or offered an explanation for the slayings. Prosecutors on Wednesday described Harris as a member of the No Limits faction of the Black P Stone street gang.

"I wouldn’t suspect he picked four random people on the street," Deenihan said. "That wouldn’t make sense to me."

According to prosecutors, several witnesses identified Harris as the shooter.

Deenihan couldn't say whether the victims had been linked in any way to the slaying of Harris' father, who Deenihan said had 47 arrests on his record and two murder charges.

“A more than reasonable person would believe he was seeking revenge for the murder of his father," Deenihan said.

According to prosecutors, the four victims were standing outside Nadia Fish & Chicken, 2704 E. 74th St., about 3:30 p.m. March 30 when Harris emerged from a vacant lot armed with a semi-automatic handgun and opened fire. He shot two men outside, and two others dashed into the restaurant hoping "to flee the hail of gunfire," Assistant State's Attorney Jamie Santini said during a bond hearing Wednesday.

Those victims were fatally shot inside, authorities said. Police found two men dead inside the restaurant, a third victim immediately outside and the fourth man across the street in a yard.

"You are a threat to all of us," Cook County Judge Adam Bourgeois Jr. told Harris in court Wednesday. "No bail."

The slain men were identified as Edwin Davis, 32, of the 9400 block of South Ada Street; Emmanuel Stokes, 28, of the 2400 block of East 74th Place; Dillon Jackson, 20, of the 2600 block of East 74th Street; and Raheem Jackson, 19, of the 2600 block of East 74th Street.

The Jacksons were brothers and were slain in front of their mother while she worked at Nadia Fish and Chicken, according to the Tribune.

Harris faces four counts of first-degree murder.

His defense attorneys Wednesday described Harris as a lifelong South Shore resident. The attorneys said that Harris was only identified as the shooter by witnesses — not camera footage — and that there are several witnesses who can place Harris elsewhere at the time of the shooting.

"There might be a little bit more to the story" than what was presented in court, attorney Ian Barney said.

According to Santini, Harris has an extensive juvenile history that includes convictions for armed robbery, carjacking, burglary, unlawful possession of a gun, resisting arrest, violating probation and escape. There is no prior adult history.

Chicago Police Supt. Eddie Johnson said police were familiar with Harris before the shooting.

“This is his first arrest as an adult, and while I can’t go into the specifics of his extensive juvenile history, as we’ve seen too many times here in the city of Chicago, he’s no stranger to CPD nor is he unfamiliar with using an illegal handgun," Johnson said.